Technical Field of the Invention
The present invention relates to a process for artificially coloring the skin which entails topically applying thereon a composition comprising, in a physiologically acceptable medium, at least dehydroascorbic acid and/or a monomeric derivative thereof of formula (I) that will be defined later and/or an isomer thereof of formula (I′) and/or a polymeric and especially dimeric derivative thereof of formula (II) defined later, and at least one compound comprising at least one free amine function.
Description of Background and/or Related and/or Prior Art
Today, it is important to look healthy, and a tanned skin is always a sign of good health. However, a natural tan is not always desirable since it requires long exposure to UV radiation, in particular to UV-A radiation that causes tanning of the skin but, however, is liable to induce an adverse change therein, in particular in the case of sensitive skin or of skin that is continually exposed to solar radiation. It is thus desirable to find an alternative to a natural tan that is compatible with the requirements of such skin types.
Most of the cosmetic products intended for artificially tanning the skin are based on carbonyl derivatives which, by interacting with the free amine functions of the skin, in particular the amino acids, peptides or proteins of the skin, permit the formation of colored products.
To this end, it is known that dihydroxyacetone, or DHA, is a particularly advantageous product which is commonly included in cosmetics as an agent for artificially tanning the skin; when applied to the skin, in particular to the face, it provides a tanning or bronzing effect which is similar in appearance to that which may result from prolonged exposure to sunlight (a natural tan) or under a UV lamp. Moreover, DHA-based products, by providing a tanned, healthy appearance, allow skin imperfections to be concealed.
One drawback of DHA is the length of time the coloration takes to develop: specifically, several hours (3 to 5 hours in general) are required for the coloration to be revealed. Another drawback of DHA is its tendency to produce yellow shades that harm the production of a natural skin tone. There is thus increasing demand for coloring products for the skin that act quickly and provide a coloration closer to that of the natural color of the skin. Moreover, self-tanning agents such as DHA cannot produce an adequate tone on dark skin.
Thus, need continues for novel compounds and novel compositions that can give the skin an artificial coloration close to that of natural skin color in a simple, effective and fast manner, and for any type of dark or fair skin.
WO 2005/039510 discloses the use of dehydroascorbic acid or a salt thereof produced in situ via enzymatic oxidation, as a fixing agent in the permanent waving of hair. DE-19745354 also discloses the use of dehydroascorbic acid in combination with particular compounds with primary or secondary amine groups or hydroxyl groups, for coloring the hair.